Diagnosis of Experimental Encephalitozoonosis in Rabbits by Complement Fixation

Abstract

A complement-fixation (CF) test has been developed for detection of experimental encephalitozoonosis in rabbits. The antigen consisted of disrupted homogenates of Encephalitozoon cuniculi spores grown in and released from rabbit choroid plexus tissue culture cells. The test was sensitive and capable of detecting experimental encephalitozoonosis in rabbits as early as 15 days after intracerebral infection. The test was specific for infected animals, and no cross-reactivity was demonstrated between E. cuniculi antigen and Nosema apis, Trypanosoma congolese, Trypanosoma cruzi, rabbit liver powder, rabbit brain powder, and rabbit choroid plexus cell culture. Sera from rabbits infected with Toxoplasma gondii, Eimeria stiedai, and Eimeria perforans did not exhibit antibodies to E. cuniculi. No CF-inhibition activity was detected.

Role of antibody and complement in the control of Encephalitozoon cuniculi infections by rabbit macrophages

“…Rabbit fibroblasts grown in Earle minimum essential medium were used instead of rabbit choroid plexus cells. Parasites were isolated by rupture of the host cell, filtration, and washing (39).…”

Biology and Diseases of Rabbits

“…Histologic examination of tissues and observation of the organism is definitive. Other tests include the complement fixation test, an immunoperoxidase test (Wosu et al, 1977;Gannon, 1978), a microagglutination test (Shadduck and Geroulo, 1979), and an enzyme immunoassay (Cox et al, 1981). Many different serologic tests exist for the organism.…”

Opportunistic Infections: Toxoplasma, Sarcocystis, and Microsporidia

“…E. cuniculi is able to survive and replicate within parasitophorous vacuoles in macrophages due to an absence of phagosome-lysosome fusion , but pretreatment of spores with antiserum resulted in phagosume-lysosome fusion and reduced infectivity of surviving organisms (Weidner, 1975;Niederkorn and Shadduck, 1980;Schmidt and Shadduck, 1984). Complement fixing antibodies also have been detected against microsporidia and were the basis of a diagnostic test in rabbits (Wosu et al, 1977). The function of these complement fixing antibodies in resistance in vivo is unclear, since it is unlikely that the spore coat of a mature microsporidian can be penetrated by complement fixation, although less mature stages may be susceptible (Niederkorn and Shadduck, 1980;Schmidt and Shadduck, 1984;Didier and Bessinger, 1999).…”